Multiple carrier technology may be called carrier aggregation technology. Unlike a conventional general wireless communication system using only one carrier in uplink (UL) and downlink (DL), multiple carrier technology produces an effect as if a frequency bandwidth of a broadband is logically used by physically aggregating a plurality of carriers in the frequency domain in order to support an extended bandwidth.
Meanwhile, uplink control information includes scheduling request, acknowledgement or negative acknowledgement (ACK/NACK) for UL transmission, and UL channel status information. In a conventional single carrier system, the uplink control information is basically transmitted through an uplink control channel. Alternatively, if there is transmission over an uplink data channel in a circumstance in which the uplink control information should be transmitted, the uplink control information may be transmitted through the uplink data channel.